new step mom advice needed

Ana
Ok ladies im hoping to get your opinion on this one.. I've recently moved into boyfriends home temporarily while we wait for our new house that we purchased together to close. He has 2 children almost 10 and 8 years old who live with us 50% of the time. I have quickly discovered I have no personal space to study, keep my possessions or get ready for work in the morning without waking up the rest of the house. The new home we bought together has 4 bedrooms. 2 upstairs and 2 downstairs. The master is upstairs so my boyfriends plan is to have the kids each have their own room on the main floor but sleep in the 3rd room upstairs to be on the same level as us. This morning I asked if I could have one of the main floor rooms as my office/dressing room for my own personal lady space. This would allow me to go to the downstairs bathroom to shower and straight into my dressing room to not wake anyone up and not have to get ready in the dark upstairs. Also, give me a study/work area that is off limits to the kids. My boyfriend didn't think this would work. He thought the room upstairs was too small for a kids permanent bedroom (even tho it fits a full queen bed and has a closet). Anyways... I'm new to having kids in my life so my question to you guys is....am I being unreasonable? Does this request seem fair? We are talking more about it tonight and I want to come up with a solution that works best for everyone. Thanks :)